Until now, the best GPU for mining was the Nvidia GTX 1080Ti and while Nvidia Titan V yielded 30 percent more power, it cost 3x the money too. The new Nvidia RTX 2080Ti is many times more powerful than the Nvidia 1080Ti but it is not better in terms of mining. So just like the Nvidia Titan V, we may get around 30-50 percent more performance.